OBJECTIVES: a) The role of brainstem auditory nuclei in aging rats - labeled 2-deoxyglucose will be injected in rats of various ages to identify isofrequency regions of several brinstem nuclei. Nissl-stained material will be used to examine perikaryal size and packing density and overall changes. b) Friendships throughout the life cycle -the characteristics or parameters of aging, how friendships function at different ages and how they affect psychological and health factors will be studied. c) Generational differences in the perception of aging -the generational differences in the meanings of structure of self-attributed success in life as a major component of life satisfaction will be examined.